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Title: Numerical simulation of drift-resistive ballooning turbulence in the presence of the GA mode in the plasma edge tokamak

Journal Article · · Plasma Physics Reports
;  [1]
  1. Russian Research Centre Kurchatov Institute (Russian Federation)

Drift-resistive ballooning turbulence is simulated numerically based on a quasi-three-dimensional computer code for solving nonlinear two-fluid MHD equations in the scrape-off layer plasma in a tokamak. It is shown that, when the toroidal geometry of the magnetic field is taken into account, additional (geodesic) flux terms associated with the first poloidal harmonic ({approx}sin{theta}) arise in the averaged equations for the momentum, density, and energy. Calculations show that the most important of these terms is the geodesic momentum flux (the Stringer-Windsor effect), which lowers the poloidal rotation velocity. It is also shown that accounting for the toroidal field geometry introduces experimentally observed, special low-frequency MHD harmonics-GA modes-in the Fourier spectra. GA modes are generated by the Reynolds turbulent force and also by the gradient of the poloidally nonuniform turbulent heat flux. Turbulent particle and heat fluxes are obtained as functions of the poloidal coordinate and are found to show that, in a tokamak, there is a 'ballooning effect' associated with their maximum in the weak magnetic field region. The dependence of the density, temperature, and pressure on the poloidal coordinate is presented, as well as the dependence of turbulent fluxes on the toroidal magnetic field.

OSTI ID:
21443498
Journal Information:
Plasma Physics Reports, Vol. 36, Issue 7; Other Information: DOI: 10.1134/S1063780X10070019; Copyright (c) 2010 Pleiades Publishing, Ltd.; ISSN 1063-780X
Country of Publication:
United States
Language:
English